How Are Overweight and Obesity Diagnosed?

The most common way to find out whether you’re overweight or obese is to figure out your body mass index (BMI). BMI is an estimate of body fat and a good gauge of your risk for diseases that occur with more body fat. The higher your BMI, the higher your risk of disease. BMI is calculated from your height and weight. You or your health care provider can use the chart below or the National Heart, Lung, and Blood Institute’s online BMI calculator to figure out your BMI.

Body Mass Index for Adults

* Weight is measured with underwear but no shoes.

Use this table to learn your BMI. First, find your height on the far left column. Next, move across the row to find your weight. Once you’ve found your weight, move to the very top of that column. This number is your BMI.

What Does Body Mass Index Mean?

Although BMI can be used for most men and women, it does have some limits:

• It may overestimate body fat in athletes and others who have a muscular build.
• It may underestimate body fat in older persons and others who have lost muscle.

Body Mass Index for Children and Teens

Overweight is defined differently for children and teens than it is for adults. Because children are still growing and boys and girls mature at different rates, BMIs for children and teens compare their heights and weights against growth charts that take age and sex into account. This is called BMI-for-age percentile. A child or teen’s BMI-for-age percentile shows how his or her BMI compares with other boys and girls of the same age.

For more information about BMI-for-age and growth charts for children, go to the Centers for Disease Control and Prevention’s BMI-for-age calculator.

What Does the BMI-for-Age Percentile Mean?

Waist Circumference

Health care professionals also may take your waist measurement. This helps to screen for the possible health risks that come with overweight and obesity in adults. If you have abdominal obesity and most of your fat is around your waist rather than at your hips, you’re at higher risk for heart disease and type 2 diabetes. This risk goes up with a waist size that is greater than 35 inches for women or greater than 40 inches for men.

You too may want to measure your waist size. To do so correctly, stand and place a tape measure around your middle, just above your hipbones. Measure your waist just after you breathe out.

Specialists Involved

A primary care doctor (or pediatrician for children and teens) will assess your BMI, waist measurement, and overall health risk. If you’re overweight or obese, or have a large waist size, your doctor should explain the health risks and find out whether you’re interested and willing to lose weight. If you are, you and your doctor should work together to create a treatment plan. The plan should include weight loss goals and treatment options that are realistic for you.

Your doctor may send you to other health care specialists if you need expert care. These specialists may include:

• An endocrinologist if you need to be treated for type 2 diabetes or a hormone problem such as an underactive thyroid.
• A registered dietitian or nutritionist to work with you on ways to change your eating habits.
• An exercise physiologist or trainer to figure out your level of fitness and show you how to start physical activities suitable for you.
• A bariatric surgeon if weight loss surgery is an option for you.
• A psychiatrist, psychologist, or clinical social worker to help treat depression or stress.